Two couples had babies in the same hospital at the same time. Michael and Danielle had twins, a boy, Michael, Jr., and a girl, Michelle. Denise and Earnest had a girl, Tonja. Danielle was convinced that there had been a mix-up and she had the wrong girl, since Michael Jr. and Tonja were both light-skinned, while Michelle had darker skin0. Danielle insisted on blood type tests for both families to check whether there had been a mix-up. In order to interpret the results of the blood type tests, you will need to understand the basic biology of blood types.
Now you are ready to evaluate whether Earnest and Denise's baby girl was switched with Michael and Danielle's baby girl. The following family tree shows the blood types for both families. Is it possible for Michael and Danielle to have a child who has type O blood? How do you know this?
Please be thorough with your answer or points will be deducted. Was a switch made at the hospital? How could fraternal twins be as different in appearance as Michelle and Michael, Jr.—including one having light skin and the other having dark skin?
Please be thorough with your answer or points will be deducted.